%\usepackage{xcolor} % declare before tikz to avoid conflicts

\usepackage{tikz}
\usetikzlibrary{matrix,arrows}

\tikzstyle{instr}=[rectangle, draw=black!85!black, text centered, text width=3.5em, minimum height=1em] % instruction
\tikzstyle{dinstr}=[instr, dashed] % dashed instruction
\tikzstyle{minst}=[row sep=.5em, column sep=2em, minimum width=1em] % matrix
